TYMPANOPLASTY 343 1. Myringoplasty (Fig. 176, A). 2. Attico-antrostomy is indicated where the ossicular chain is intact but where a marginal or attic perforation, granulations or cholesteatoma indicate underlying bony disease which must first be completely removed. Recon- struction may require use of fascia only or fascia plus homologous incus or cartilage if the ossicular chain has been interrupted by excision of diseased tissues (Fig. 176, B). Fig. 176. Tympanoplasty. A, Myringoplasty; B, Attico-antrostomy with, application of graft; C, Columella type of tympanoplasty; D, Total tympanoplasty (baffle effect). 3. A type three repair is possible where there is an intact mobile stapes. After removing all bony disease the graft is applied from the remnants of the drumhead or adjacent meatal wall to the facial ridge and inner attic wall, thus reconstituting a middle ear cavity. The graft is in direct contact with the head of the stapes so that a columella type of conduction is obtained (Fig. 176, C). 4. Type four tympanoplasty is indicated when the ossicular chain is disrupted and the only remaining part of the stapes is a freely mobile foot- plate. A columella type reconstruction may be obtained by a homologous T-shaped cartilaginous graft from fascia to footplate or else the oval window is left exposed in the cavity while a baffle is constructed which provides sound protection for the round window. This is achieved by forming a pouch between the Eustachian tube and the round window, the pouch being covered with a fascial graft (Fig. 176, D). 5. When free mobility of the stapes is unobtainable on account of tym- panosclerosis, excision of chronic disease may be followed at a second operation by fenestration of the lateral semicircular canal, a type five tym- panoplasty. Such a procedure presupposes good cochlear function.